Bidule 111

[lenb]

Asher, I made a backer behind the spinner ring like you did although I opted not to put a screw there because you will always have to pull the prop and spinner to get the top of the cowl off. It has seemed to work out well. No issues so far.
Nice work on the Bidule Jr.


Len

[Asher Carmichael]

Guys,
Thanks for the comments. For me, the Bidule is intended to be a workhorse with minimal bling, including no spinner at least in the beginning, so removing the top of the cowl will be straightforward. Besides, I doubt this thing will win any beauty contest, even with a spinner. ;-)

[Swiss1]

Remember you have the Drag Queen for the Beauty Contest

Jeremy and Ben
SCC AAA TT TN

[Asher Carmichael]

Remember you have the Drag Queen for the Beauty Contest

Jeremy and Ben

IT wins every time

[Asher Carmichael]

I'm on the downhill side on the 111, which includes exhaust and landing gear. The 111 is too narrow for K&S canisters and comfort mounts. Even with the cans touching, the mounting lugs fall just to the outside of the fuselage. To remedy this, I used a piece of aluminum "Z" channel from McMC. I used 8-32 cap screws through the fuselage for the inboard mounts and #8 pan head screws right at the outboard location to mount the assembly.

[Asher Carmichael]

Here is a pic of the inside showing hard point dowels inserted between the bottom and the servo tray to receive the 8-32 cap screws for the canister mount.

[Asher Carmichael]

One of the nice things about external cans is that you can braze the headers and pipes in situ which means no flex headers required!! I start out fitting, cutting and assembling all the pieces in place. Since there is no flex, the cans will be angled a bit in order for the headers to align with the exhaust ports on the engine. You'll need to do all this cutting and fitting before drilling the "Z" channel for the canister studs to ensure there is as little tension on the assembly as possible. I then remove the exhaust flange and first piece of header pipe and braze them off the model. Reassemble and start brazing. If you wind up with a joint that is hard to access all the way around, just tack as much as you can and you can finish up when you remove the header from the model for cleanup. BTW, you'll want to employ a heat barrier fabric as shown here. McMC part 8851K33. I use DA silver brazing rod and a Mapp gas torch. Can't say enough about this brazing rod. I also found this handy little torch shown here. Its easier to use than a bottle-based head and not as bulky as the hose based unit from Bernz-O-Matic which is comparably priced. http://zorchproducts.com/propanemapp-torches.html

[Asher Carmichael]

After following Len's and Bob's thoughts regarding a bellcrank for the nose gear steering I thought I'd try this idea which requires few mods other than the addition of a piece of 1/8" aluminum angle, a bellcrank, and some #8 screws. It does require removing part of the front of the tray against the firewall to allow room for the nuts. You'll notice in the video that I opened up a good portion of this area to allow nuts to be used on the nose gear attachment screws. I stripped one of the "T" nuts when trial fitting the gear and decided that all the bolts needed additional security. Len/bob, I think I remember one of you mentioning that a bellcrank system might allow use of the servo saver Bob found rather than the rubber vibration mount supplied. I'm thinking I'd like to get rid of it and try the Integy servo saver. I picked one up and it appears to be a nice item. Think it will work? Here's a quick video. https://youtu.be/T4g4k5E6HmQ

[Asher Carmichael]

Here are the components of the bellcrank. The flanged sleeve and shaft bearings are Delrin and the bellcrank is .093 G-10. 10-32 screw mount.

[Asher Carmichael]

After pondering and working with the bellcrank design I have finalized it as shown in the drawing. The output leg of the arm is longer than the input or servo side which gives more throw. The steel arm on the gear itself has been shortened to about 1" which provides more movement and helps clear the gas input nipple on the carb. I have removed the vibration mount servo saver provided with the kit and replaced it with an Integy heavy-duty servo saver as Bob M mentioned in his post on the Bidule 170 http://www.integy.com/st_main.html?p...1#.VedCBzhRGUk Part # C25755GUN I did have to open up the pushrod port on the firewall to allow room for the increased length of the servo arm. It needed just a bit of radius on the lower inside corner to allow the ball joint arm to clear. Hopefully this will work. Sorry about the small size of the drawing. I can't seem to figure out how to upload a file that is reasonable in size or that can be enlarged. If anyone is interested, just PM me and I'll send a DWG or PDF.

Here's a video of the updated system.

https://www.youtube.com/watch?v=e3d1QcILbjE

[BobM]

Looks really good Asher.....I have to think about doing something like that on my steering possibly. I'll probably stick with mine for now until I need to work on it again and then modify it.

[Asher Carmichael]

Always the tinkerer. I've decided the servo saver is too "soft" for the system so I've gone back to the original vibration mount with a twist. I located a heavier mount at McMC and placed it at the servo end as shown in the photos. You can see the smaller original version and the new and improved one. It seems to have just the right amount of stiffness and give for the system. It's a drop-in replacement. Did someone say Goldilocks?

McMaster Carr part # 9217K32

[lenb]

Asher.
Is that the original placement of the shock ?
On the larger mode the shock is up by the firewall. The tube is bent, then the shock is located. The design is for the pushrod to "break" at the shock when the nose wheel takes a jolt.
This works pretty well and I've been using the stock setup since day one. I tried to support the tube in the middle so it wouldn't flop around as much but that made it too stiff and it broke a servo output shaft after only 10 hrs. So back to stock for now.

So far I've put about 35 hrs of towing on the Bidule. Its a fantastic tow plane, so making the nose wheel shock system a bit more reliable is a home run.

Scot and I working on a large servo saver design used for big RC trucks. Parts have been ordered, we'll post progress as soon as we have something to show.


Len

[Asher Carmichael]

Len,
No, it is not the original placement. The 111 is designed like the 170 but the tube is not bent. The addition of my bellcrank design gave me significant throw but there isn't a lot of room to add the shock in the original position on the short pushrod. My theory is by placing the shock where I have, the collapsing moment arm is changed and stiffens things up. This system I've devised still flexes as you've mentioned but there is definitely more stiffness than stock. I'll be interested seeing what you and Scot design and I'll post results of my trials here as well.

[Asher Carmichael]

Landing gear down.....
I used Dubro 6" lite wheels on the mains and a 5" on the nose gear. We'll see how long they last.
I also added a piece of stainless steel tubing on the nose gear to cover the axle bolt so the wheel won't rub directly on the threads of the bolt. McMC had steel thin wall tubing that was a perfect match for the 5mm socket head axle bolt.

McMC part # 50415K27

Delrin spacers were bored and turned on the lathe to fit over the stainless tubing for the nose gear. Cotter pin safety clips were added to the main axles.